I have a Tempest-X 15" sub and was going to throw it into a fully stuffed 200 liter enclosure (it will be sourrounded--built in- with a entertainment centre and mounted facing out to listening area and powered by a 500 wat BASH amp. I got looking at the 1/2 wedge designs-- would I gain anything much by building a 1/2 wedge and simply extending the box to the side for the extra volume needed and have the mouth of the wedge opening facing out and therefore near the corner of the room?

Would one stay with the specified opening width in the blueprints for a 15" driver with healthy X max?

This may be a little vague as I re-read it if so I could try to clarify if someone would jump in.

I think it would prolly work fine. My main reason for going with the Half-Wedge was I had already try the other types of enclosures. First was sealed , next ported, and iso-loaded ported. The HWK18 was too big and even fouth-order BP was going to be large for the sub I was using. I took a 8ft^3 ported enclosure and chop it in half and made me a couple of wedges. The wedges outperform all the others I had tried. Lower frequency response, better spl, and the enclosure was not so huge.

I think the Half-Wedge will be exactly what you want but that is my $0.02.

An after thought: the depth measurement on my sub will be 26" and the plans state that there needs to be 1" from the floor at the beginning of the slope were the driver is mounted and the plan states and opening size for the exit--is there a relationship for a "correct slope vs output opening size"?

The reason I ask is that if I were to port this driver it requires an 8" port according to Kevin at Exodus Audio to avoid port noise down deep. In other words is there a magic formula that needs to be adhered to regarding the start height of the slope from the floor, the width of the slope and the exit height of the opening?

There is no formula that I know of. I would to keep the ratio the same as the original or as close as possible. I would prolly go two inches at the rear just because of the sub you are using. When changing a design and usually going bigger, it is a guessing game but i would error on the side of large.